The following discussion of the prior art is intended to facilitate an understanding of the invention and to enable the advantages of it to be more fully understood. It should be appreciated, however, that any reference to prior art throughout the specification should not be construed as an express or implied admission that such prior art is widely known or forms part of common general knowledge in the field.
The most significant problems in designing climbing robots relate to balancing the robot weight with mobility and the adhesion system. All of these design problems interrelate and all are heavily dependent on the robot's operational requirements and intended environment.
One class of climbing robot uses wheels for mobility and an adhesion system to hold the wheels in contact with the climbing surface. While wheeled robots require low control complexity and can achieve high climbing speeds, they typically lack capability dealing with uneven surface. As with non-climbing vehicles, most wheeled robots are unable to cope with complex plane transitions, and the ability to span discontinuous surfaces. The problems are only exacerbated for climbing robots dealing with complex transitions and overcoming gravity. To overcome gravity, wheels with active adhesion, such as magnetic adhesion, are required. Wheels incorporating magnetic adhesion will accumulate ferromagnetic dust which eventually leads to failure in adhesion and jamming.
On the other hand, legged robots tend to be a slower form of locomotion, although they can overcome many of the problems faced by wheeled and tracked locomotion because by sitting further from the surface they typically have the ability to step over obstacles or transition to other planes. However, this also results in a significant shortcoming in that with the increased spacing from the surface, the lateral detachment moment increases for a given body weight. Furthermore, in order to support the weight of the robot actuators used for joints must be stronger than those used for wheel and tracked locomotion. Accordingly legged robots typically require improved adhesion systems.
To date, no acceptable solution has been identified for balancing weight with the required mobility to traverse complex surfaces.
It is an object of the present invention to overcome or substantially ameliorate one or more of the deficiencies of the prior art, or at least to provide a useful alternative.